Fight to the left, enter and clear Netherflame Forge, concluding with The Doomsmith. Best place for the Doomsmith fight is the rocks in the middle to avoid the hammer adds. If the hammers respawn and one gets to the Doomsmith, it empowers him to cast an elemental AE that will probably wipe the party. In here you will find a forge for special crafting, 5 plinths with glyph keys on them (this will be important later), and a glowing book on a table which starts the quest, Something Greater. The only thing you need for this, the Flint Streaked Summoning Orb, is an auto-update when you kill Firelord Kaern.

Now clear any remaining mobs you left on the pathways before facing the Sub-Boss, Cruhm the Overseer. Not a difficult fight. when he gets low he will break off the fight and try to summon a Greater Elemental to destroy you, but it is more than he can control and, instead, it kills him. In the center of the lava curtain will be a series of 5 glyphs, matching the plinths in the Netherflame Forge. Return there and click them in order, top to bottom, to open the lava curtain. You could have opened the curtain at any time, but you would still have to get past Cruhm...

Cross the bridge to find the Magmaborn Furnaces. Pull groups to the bridge until you get a clearing, then enter and move left or right (it does not matter which you do first) to a valve. One of you turn this while the rest handle the mobs. Return to the bridge and repeat to the other side. With both valves turned, the pit in the center floods with lava, killing all the other mobs there.

Now for the final fight... Firelord Kaern. Throughout this fight he will drop a Pool of Lava here and there. The Pool will deal significant AE heat damage to anyone around it. So, here is how you do this fight. The tank has to drag Kaern around the room, moving pretty much constantly, with everyone else backing and blasting. Do not ever get behind him and you won't get hit by the AEs. However, the Pools do not de-spawn, so you have ONE loop around the room to kill him. If you get back to where you started you will all die. Ranged DPS is key to this fight, and lots of it.

Once he is dead, the bonus shard chest sits beside his throne, and the magma rocks (for Liquid Hot Mag-ma) are around the lava pit with the last one above the throne.

We had a group in this instance last night. Fairly easy zone once you get past "the door", which is referring to the wall of lava that keeps you out of the back of the zone. If the wall of lava cannot be passed by, then you must know the proper sequence to activate the symbols in the room off to the side. If you don't KNOW the sequence, then killing Cruhm the Overseer will make the runes appear inside the lava falls, and you must activate them in order, starting at the top rune on the falls. Good Luck!!